Development of a myocardial phantom and analysis system toward the standardization of myocardial SPECT image across institutions

Technical Note: Development of an ischemic defect model insert attachable to a commercially available myocardial phantom

OBJECTIVE

The purpose of this study was to develop a novel myocardial phantom insert model that attaches to commercially available myocardial phantoms and simulates an ischemic area, using three-dimensional printing technology.

METHODS

Ischemic inserts were designed to give four levels of absolute percent contrast (Low; 10%, Medium; 20%, High; 35%, and Defect; 100%) using CT images and computer-aided design software. The ischemic insert was composed of multiple slit structures to replicate myocardial ischemia. Myocardial phantom images with developed ischemic inserts were acquired using a SPECT/CT system and were then reconstructed using filtered back projection (FBP) and iterative reconstruction (IR) with various cutoff frequencies of a Butterworth filter. The performance and utility of ischemic inserts were evaluated according to percent contrast and 5-point scoring.

RESULTS

The percent contrast and scoring results changed according to the ischemic insert type, cutoff frequency, and reconstruction method. The percent contrast of each insert obtained by FBP with 0.4 cycles/cm was 4.1% (Low), 15.7% (Medium), 17.4% (High), and 36.1% (Defect). Similarly, the percent contrast of each insert obtained by IR with 0.4 cycles/cm was 5.0% (Low), 17.0% (Medium), 21.9% (High), and 47.7% (Defect).

CONCLUSIONS

We successfully developed an ischemic insert that attaches to a commercially available myocardial phantom by using CT imaging and 3D printing technology. Our proposed ischemic insert provided several abnormal perfusion patterns on myocardial SPECT images and may be useful for evaluating SPECT image quality.